rebuilding a chevy small block marine engine

[altemusj]

I just bought a 33 ft Owens Express. It needs two motors, I need to find 2 chevy smal blocks,otherwise i have all the parts. Are their any good books that go step by step on rebuilding a chevy small block marine engine.


thanks

Captain Alty

[mobjack68]

Bountiful information on the net.....google it. And don't use marine supply houses to buy marine parts unless you absolutely have to. They charge about 3 times what an auto parts store charges.

[Bob Adams]

Howdy Captain.

The Owens Flagship engines were based on 327 blocks, so the 350s you will probably be replacing them with will need but 2 modifications.
1. Use the original camshafts.
2 Dry fit the aluminum oil pan, turn the engine over by hand and note the areas you will have to grind clearance for the crank.

Other than that, there are tons of referance books on rebuilding small block Chevys.

Good luck.

[machineryman]

I have what I think is the same boat and engines that you have. Mine has OWENS/Paragon transmissions also. You have two different engines, one counter rotation, port side, and one standard rotation, starboard side. They are 327 chevrolet engines of a 1964 style, even though my boat was launched in 1968. Forget the advise about using automotive parts, as the distributor, fuel pump, alternator and carburetor all MUST be ignition protected marine units unless you want to blow your boat and whoever is aboard to kingdom come. You can rebuild the engine with internal automotive parts, i.e., rings, bearings, oil pump, most gaskets, etc, but the counter rotation engine will need a different cam shaft and rear seal and must have the pistons turned in the proper direction.

I had one engine rebuilt because of the rust and machining required, but had another machined and assembled the engine myself with the help of an old Corvett engine manual. These engines were used in Corvetts in 1964.

Send me an email and I'll give you more detailed info. You could also look for a couple of modern 350 CI engines, one being counter rotation, and use your old oil pans and manifolds plus carb, fuel pump, etc..

Bob C.

[brad9798]

craigslist is a great place to pick up 'blow' engines ... out of boats. Most of the time they really are not destroyed ...

[Krunch]

FWIW, here's a link to a 14 MB PCM Service Manual:

http://www.correctcraftfan.com/Downloads/PCMsvcmanual.pdf

[Terrence Gilhuly]

Hello Captain,

I have one rebuilt 327 (RH rotation) with a Paragon transmission.
Only a hundred or so hours on the rebuild.
PM me if interested.
Where are you located?

Terrence

[BBSebens]

fortunately, you are talking about one of the most common engines in existence. I would go with the 350's simply because there are so many parts available, new used, or my favorite: upgraded. maybe think about upgrading to fuel injection? not a difficult modifictaion.

look on amazon, or your own favorite online retailer, a how-to book on rebuilding a 350 should be fairly easy to locate.

[Canoeyawl]

The marine and truck versions have steel cranshafts, look for four bolt mains. The car version is cast iron crank, Not so good for continuous duty.

[seo]

This is an apocryphal story, with elements of truth. But which elements?
Well, anyway, the story is that Mercruiser has/had a special relationship with GM, and could get engines with forged cranks, steel cranks, special cams, etc, all reflecting mercruiser's experience with marine engines.
I have it on pretty good authority that there was a period back in the '90's when if you ordered a Corvette with the big horsepower fire-breathing big block engine, it would have been assembled by Mercruiser, not GM.
As an aside, you might consider going with the GM V6, which I think is nothing but a small block V8 with two cylinders removed. With 262 cubic inch displacement, they're about the same size as the old time 283 small block, and are a more economical engine, and lighter.

[Peter Malcolm Jardine]

Are the motors non existent? If not, are the blocks cracked? If so, you can just find blocks. I assume you are not doing the machine work. The standard process is to disassemble the motors, check all parts, get the machine work done, then reassemble.

Things to check and replace

Armatures in the starters do corrode over time, starter drives wear
Brushes in the original alternators, cleaning and corrosion.
Bearings, seals, and impellers in the raw water pumps.
Pressure test on the transmission or oil coolers
complete disassembly and corrosion check of the manifolds
A complete valve job is usually required on the original heads if you are using them... they are before hardened valve seats and unleaded gas.
Temp senders, oil pressure senders usually should be replaced
All new gaskets and bearing assemblies for the engine
If an existing iron intake manifold is used, check the exhaust baffle under the carburetor for rot... a usual problem on chev marine conversions of the sixties

New plug wires, voltage regulator, plugs, etc
If your tachometers are electric, a new HEI style distributor, with an MSD performance ignition... saves money on fuel, which is a consideration on a boat that big.

If a rebuildable core is used, yes the marine version would have a forged crank, then the engine is bored, new 30 thou over pistons are installed, new crank bearings, the crank is turned 10 thou smaller (sometimes on a low hour marine engine the crank can be polished) all new valve springs, valve guides, new hydraulic lifters, a new oil pump, as well as all other things mentioned.

A modern 350 engine with a modern carburetor and intake, as well as HEI ignition, will overpower an older hydraulic transmission.

The older paragon and borg warner trannies are still supported for parts, but some parts are getting tougher to get. Paragon RB reduction gears are no longer supported by Great Lakes Power.

Make sure the engine block receives BRASS frost plugs, not steel.

The engine block should be tanked, cleaned, and probably magnafluxed to check for cracks.. although when marine engines crack, it is in a spectacular fashion.

I personally don't recommend rebuilding an engine that requires 60 thou boring to be cleaned up, except in some specific cases.

All parts should be primed, then painted in a good quality automotive paint, or rust paint. It's a good opportunity to clean and repaint the bilge, as well as install drip pans under the engines.

Likely bill, for machine work, parts, etc, given that you do all the assembly and disassembly... $8000 or so.

[Don Z.]

This is an apocryphal story, with elements of truth. But which elements?
Well, anyway, the story is that Mercruiser has/had a special relationship with GM, and could get engines with forged cranks, steel cranks, special cams, etc, all reflecting mercruiser's experience with marine engines.
I have it on pretty good authority that there was a period back in the '90's when if you ordered a Corvette with the big horsepower fire-breathing big block engine, it would have been assembled by Mercruiser, not GM.
As an aside, you might consider going with the GM V6, which I think is nothing but a small block V8 with two cylinders removed. With 262 cubic inch displacement, they're about the same size as the old time 283 small block, and are a more economical engine, and lighter.


Only Corvette engine in the 90s was a small block, not a big block. The "new" LT1. 350 cubic inches.

The big blocks were built in Tonawanda, NY. Plant 4. Go ahead, ask me how I know...

GM sent the engines to Mercruiser for mods. Mercruiser did not send built big blocks to Bowling Green.

The Vortec 4.3 litre 6 was basically a small block with two cylinders lopped off. But not the "same size as the old 283". 283 block was the same block as the 350. Just change the bore and stroke. 3.875 bore, 3 inch stroke, you have a 283. Bore that out to 4 inches, you'll have a 302 (remember those?). Stroke that to 3.25, there's your 327. Stroke some more to 3.48, now you're talking 350. Same basic block, though...

[Dan McCosh]

GM has a marine engine engineering center in Mt. Clemens, MI, that does the modifications to its engine blocks for marine use. They blocks go out to engine "bullders", like Mercruiser. Anyway, the small-block is usually a pretty inexpensive rebuild. The last guy I knew who had one done was for about two grand a block--but that was about 15 years ago. If you have the bolt-ons, shopping around for a rebuilder should be relatively easy.

[seo]

RE: the big block chevy

What mods did they do at Mercruiser? Did any of those engines ever find their way into Corvettes?

One of the problems with keeping track of Chevies is that their engine designations became famous. As I understand it, "Z28" was a high performance engine option, a version of the 283, or was it the 302, 305? Whatever, "Z-28" achieved such fame that I think there were Camaro models with "Z-28" stickered all over it. Did they all have the Z-28 option engine?
Same question with the L-88. Years ago I spent a few miles riding in and driving a Corvette with an L-88 engine. It was as intractable as a full-race engine, but my goodness wouldn't it peel the tread off the those tires.
Anyway.
The local machine shop will rebuild a chevy small block for "hundred fifty a hole," which includes pistons, rings, valve job, bearings, crank polished, not turned.
I have sat politely and listened to long involved arguments on the subject of whether the four-bolt block is really better, just a gimmick, a commie plot, the Second Coming, or whatever. It makes sense that it would be better, but it also makes sense that GM wouldn't go broke when confronted with Toyota.

[BBSebens]

Sweet! a car discussion on a boat forum! I believe this qualifies as hijacking!

the real Z-28 Camaros came with the sweet fairly high revving 302's, which were great for road and track racing. the SS had a 350, 396 or other depending on year.

I believe the L-88 Vette (a moment to wipe the drool from my chin) had a 454 Big block. can you hear the huge sucking sound of fuel? not over the exhaust you can't.

yes a 4.3 V6 (283) is a 350 with the back cylinders lopped off. both great motors. Its the reason you can put a 350 in your v6 S-10 without too much trouble.

back to the point. the Chevrolet 350 ci Small Block V8 is quite possibly the most produced and most imitated, certainly the best known, motor out there. there are probably thousands, maybe a million, of them out there, and lots of them have been rebuilt at home, with the machining done at a shop. If your a boat guy, I think you can handle it if your not in a hurry, and if you have a wooden boat, I dare say you know how to be patient and do it right.

[Don Z.]

Z-28 was actually the option code. The original included the 302 engine, as well as suspension parts, etc. Ditto on the engine codes like L-88, L-82, LT-1. It's what the dealer would mark on the form to get you what you want.

Z-28 then became a model designation...

Oh, and they made the 302 for no other reason that for a couple of years, the race series (Can Am? Or was it Trans Am... I sense a trend) limited displacement to 5 litres. When that restriction went away, so did the engine. But you can recreate it with the pistons from a 327 and the crank from a 283...

[Canoeyawl]

Does the Z stand for Zora???
I'll betcha...

[Krunch]

Likely bill, for machine work, parts, etc, given that you do all the assembly and disassembly... $8000 or so.

Or...for not much more than that, you could buy two new long blocks and install them.

I know what I'd do.

[Dan McCosh]

Just checked--remanufactured short block for the 5.7L Chevy is about $2,000.

[Ross M]

FWIW, the LT5 (5.7L, 4-cam V8) that powered the 1990-1995 Corvette ZR-1 was designed by Lotus and produced by Mercury Marine in Stillwater OK.

If memory serves, Mercury's experience with "lost foam" casting was a key factor.

Ross

[Peter Malcolm Jardine]

Just checked--remanufactured short block for the 5.7L Chevy is about $2,000.

That`s a good price, if the engine comes with a forged crank, the appropriate cam, and brass frost plugs.

On my Chris craft 283's I rebuilt starters, alternators, both raw water pumps, pressure tested transmission coolers, (fixed one) new eagle 30 thou over pistons, cranks were polished, new marine gaskets, rebuilt the carburetors, new bearings, rebalanced the rods, new valve seats, springs, guides, had a intake manifold exhaust baffle welded, blocks were tanked, cleaned and inspected carefully...stripped, cleaned and painted everything.. new points, condenser, plug wires, engine wires, senders, etc.

A new sherwood bronze water ^pump for my engines was 450 dollars american each. The rebuild kits were over 250 each... I made some parts and came out at about 150 dollars each kit. The marine gasket kit is about 125 dollars US each kit, depending on which manifold gaskets, and which oil pan gaskets you need. A marine rebuild is more expensive than a car rebuild, but thats just my experience.


Personally, I find you can have about a 60% good luck with assembly line remans... especially for marine use. I prefer to spend a little more time on them... since the install and removal is more of a hassle generally.

If you can rebuild two marine engines completely for less than I spent, all the power to you.

[Dan McCosh]

I just did a quick search on marine engine rebuilders, and don't know anything about their quality, or exactly what is included. A full engine is about $7,000, with the short block in the $2,000 range. That is about what it was quite a while ago when a friend did the two engines on a 42 ft. Chris Craft. I've had similar estimates (about $2,000) for my 4-cyl Gray. This generally includes the machining and labor of disassembly an reassembly. All in all, these engines are pretty inexpensive to rebuild.

[seo]

FWIW, the LT5 (5.7L, 4-cam V8) that powered the 1990-1995 Corvette ZR-1 was designed by Lotus and produced by Mercury Marine in Stillwater OK.

If memory serves, Mercury's experience with "lost foam" casting was a key factor.

Ross

I would feel somewhat vindicated in my memory triumph. If I could only remember what I thought I knew back then...

[seo]

I find it a bit odd that an engine was "designed by Lotus." Ever since the days of the Lotus Seven, Lotus cars had Ford engines, or a Renault in the Lotus Europa. When did they start designing engines?
That is an aside.
On the subject of boat engines to replace a pair of small block Chevies, I still think that a pair of 4.3 V6's would have the same power as the old V8's, with better economy, less weight, and a bit more space to make it easier to work on.

[Don Z.]

The heads were designed by Lotus...

[Ross M]

I find it a bit odd that an engine was "designed by Lotus." Ever since the days of the Lotus Seven, Lotus cars had Ford engines, or a Renault in the Lotus Europa. When did they start designing engines? ...

In the late 1960s, IIRC, starting with twin-cam heads for 4 cylinder Fords. Much like Cosworth but several years later. By 1969, Lotus had dedicated engine production facilities under construction.

By the time of Colin Chapman's death, Lotus had a 4 liter 4 cam V-8 in development for the Esprit. Maybe more importantly, Lotus Engineering - a technical consulting group - was well along in capability, ably guided by ex-Rolls Royce & BRM engineer Tony Rudd. Shortly after providing preliminary consulting services to GM on the "Indy Corvette" project, GM purchased Lotus outright and had them complete development of the LT5.

At least, that's how I remember the story :D

[Dan McCosh]

Lotus Engineering did design the overhead cam ZR-1 Corvette engineering, and still is an independent engineering group, like Rousch, Porsche, etc. Rudd also was the driving force behind the Merlin V-12, as well as the BRM F-1 engines. I don't remember any Mercruiser involvement in the ZR-1 engine, however. Rudd worked on the Merlin engines with the engineering center under German attack, and the draftsmen would scramble to fight off the incoming bombers. Interesting way to test your engine design.

[Rob Stokes, N. Vancouver]

Howdy Captain.

The Owens Flagship engines were based on 327 blocks, so the 350s you will probably be replacing them with will need but 2 modifications.
1. Use the original camshafts.
2 Dry fit the aluminum oil pan, turn the engine over by hand and note the areas you will have to grind clearance for the crank.

Other than that, there are tons of referance books on rebuilding small block Chevys.

Good luck.

If you use the original cams, get them checked carefully. GM have a habit of eating the cam lobes for the back two cylinders. And if you do use the original cams, use new lifters.

I'd replace the steel frost plugs/clean-out plugs with brass ones too. you can purchase a marine frost plug kit that should have them all

[altemusj]

I just bought a 33 ft Owens Express. It needs two motors, I need to find 2 chevy smal blocks,otherwise i have all the parts. Are their any good books that go step by step on rebuilding a chevy small block marine engine.


thanks

Captain Alty


Thank you all for your response, i really am greatful.

[Skipper George]

Hey Cap Alty,
I've got 2 - 283 / 185HP Chevy Chris Craft engines that are identical to the twin 283's I have in my 30' Owens Express Cruiser, complete with Paragon Tranny's for $2500 firm if you're interested.

Thanks

Skipper George



I just bought a 33 ft Owens Express. It needs two motors, I need to find 2 chevy smal blocks,otherwise i have all the parts. Are their any good books that go step by step on rebuilding a chevy small block marine engine.


thanks

Captain Alty

[Breakaway]

Uhhh.. this thread is 2-1/2 years old. ( and classified advertising is frowned upon round here)

Kevin